Category Archives: Audio

Audio schematic diagram



Stereo Tone Control with Line In + Microphone Mixer

This is an active stereo tone control circuit using very well known op-amp IC of TL072. The circuit include mic pre-amp and mixer control. In this design, we have two inputs: one for line (stereo), one for microphone and has control of the three audio frequency (high/treble, medium and low/bass). It also provide balance control… Read More »

100W Power Amplifier Based IC TDA7294

This is a very interesting circuit design to assemble. There are 4in1 amplifier module in a circuit board. 100W power amplifier using the TDA7294, for the VU meter uses IC LM3914. The tone control preamp uses the well-known IC 4558. The symmetrical power supply module also included in the PCB.

120W Power Amplifier + Power Supply

This is 120W power amplifier schematic using TO-3 package complementary transistors, NPN and PNP polarity. The well-known power transistor pair of 2N3055 and MJ2955 used in this circuit.  +/- 50V symmetrical (split/dual polarity) power supply with minimum 3A electric current should be used for maximum performance.

Bass Guitar Preamp Pedal

Here is the circuit diagram and PCB design for relatively low cost DIY bass guitar preamp pedal uses FET K117 or equivalent. There is a bit difficult to build this kind circuit project, it’s require a good knowledge in electronics. This preamp has several features for the bass guitar instrument such as attenuator, low cut, mid… Read More »

200W Power Amplifier Using Transistor

This is a 200W power amplifier circuit project. The circuit features high power, good definition and very low noise. It delivers about 200 watts in 4 ohms loudspeaker: a 4 ohm speaker or two pieces of 8 ohm speakers in parallel. This 200W power amplifier using the complementary transistors of 2SC5200 and 2SA1943 as the… Read More »

Small Sound Amplifier for Ears (Hearing Aid)

This is the simple project of small sound amplifier for ears or often called hearing aid device or hearing loss amplifier. This circuit was already tested on some patients and give significant improvement in the hearing ability to the patients. It consumes a very small amount of power within the range of 10 milliwatts. Furthermore,… Read More »